Hidden node collision mitigated CSMA/CA-based multihop wireless sensor networks

Hidden node collision is a significant problem in CSMA/CA (Carrier-Sense Multiple Access with Collision Avoidance)-based multihop networks such as wireless sensor networks. The RTS/CTS (Request to Send/Clear to Send)-based handshaking mechanism is not effective to solve this problem in multihop networks. Also, to reduce power-consumption, such a handshaking mechanism is not used in CSMA/CA networks such as the IEEE 802.15.4-based networks. Spatial scheduling of nodes is a classical approach to solve the hidden node problem. We apply this scheduling concept and present a network planning model to mitigate this problem without any control overhead by structuring a CSMA/CA-based wireless network in a cellular layout. For this network model, we derive the required distance between a sender and a receiver so that the minimum required signal-to-interference ratio (SIR) at the receiver can be guaranteed in the worst-case scenario. We also present an analysis to estimate network size for given traffic load under distance-dependent signal attenuation.